1. Field of the Invention
The present invention relates to an automatic developing device provided with a preheating section for heating a photosensitive planographic printing plate prior to a developing process. Moreover, it relates to an automatic developing device provided with a pre-water washing section in addition to the preheating section.
Moreover, the present invention relates to a photosensitive material processing device for processing a photosensitive material such as a photosensitive planographic printing plate with a processing liquid while being conveyed by a roller. More specifically, it relates to a roller washing method for eliminating the processing liquid adhered to the roller.
Furthermore, the present invention relates to a photosensitive material processing device for processing a photosensitive material by soaking in a processing liquid. More specifically, it relates to a photosensitive material processing device for circulating a processing liquid by suctioning the processing liquid in a processing vessel and jetting into the processing vessel.
Moreover, the present invention relates to a photosensitive material processing device for processing a photosensitive material while being conveyed by transmitting driving force to a conveying roller for the photosensitive material disposed along the conveying path of the photosensitive material.
Furthermore, the present invention relates to a photosensitive material processing device for processing a photosensitive material such as a photosensitive planographic printing plate with a processing liquid while being conveyed by a roller pair.
Moreover, the present invention relates to a preparation method for a processing liquid for preparing a processing liquid according to the capacity of a processing vessel of the above-mentioned processing device.
2. Description of the Related Art
According to a photosensitive planographic printing plate comprising a photosensitive layer formed on a supporting body made of an aluminum, or the like, a light receiving part and a light unreceiving part are produced in the photosensitive layer by exposure, and thereafter the unnecessary photosensitive layer is eliminated by performing a developing process with a developing liquid so as to form an image.
Among the photosensitive planographic printing plates, there is a so-called photo polymer plate comprising a photosensitive layer of a photo adhesion layer, a photo polymerization layer, or the like, and further with the surface protection by an overcoat layer. According to the photo polymer plate, the printing resistance is improved by firmly bonding the photo polymerization layer of the light receiving part onto the supporting body via the photo adhesion layer by being heated to a predetermined temperature. Moreover, the overcoat layer covering the photo polymerization layer is water-soluble.
Therefore, according to an automatic developing device for processing the photo polymer plate, a preheating section and a pre-water washing section are provided on the upstream side with respect to the developing section for reliably eliminating the photo polymerization layer of the light unreceiving part at the time of the developing process by eliminating the overcoat layer by brushing the surface of the photo polymer plate while supplying washing water after heating the photo polymer plate prior to the developing process.
The preheating section provided in such an automatic developing device in general heats the photo polymer plate by the radiation heat discharged from a far infrared radiation heater, and by the zone temperature in the preheating section.
The operation of heating the photo polymer plate by the preheating section is controlled by the heating temperature and the heating time. However, in order to heat in a short time, a high zone temperature should be provided. Under a high zone temperature, the rear end portion of the aluminum plate passing through the preheating section is heated to a high temperature due to the heat conduction of the aluminum plate as the supporting body of the photo polymer plate, and the rear end portion easily exceeds the upper limit temperature.
Moreover, the photo polymer plate can easily wrinkle by the thermal expansion at the time of heating, or by nipping by the conveying roller pair while being heated. Furthermore, when dispatching the highly heated plates to the pre-water washing section, adhering water to the heated plate therein results in stains.
When the heating process is attempted with a lowered heating temperature in order to avoid such a problem (first problem), the heating operation needs a longer performing time, and thus the preheating section requires a larger space.
Further, the photo polymer plates have different thermal capacities depending on the supporting body thickness and the plate size. Consequently, the heating temperature needs to be adjusted according to the thickness and the size for heating at appropriate temperature and of an appropriate duration. Therefore this adjustment of the heating temperature complicates the heating process for the photo polymer plate.
Next, among the photosensitive materials, there is a photosensitive planographic printing plate (hereinafter referred to as a “PS plate”) comprising a photosensitive layer on a supporting body made of an aluminum or the like. A PS plate processor as a photosensitive material processing device for processing the PS plate comprises a plurality of processing steps such as developing, water washing, desensitizing processes and the like. The PS plate after image-wise exposure is treated in the developing step of processing the PS plate by soaking in a developing liquid, water washing, desensitizing process using a processing liquid, such as a developing step of processing the PS plate by soaking in a developing liquid, a water washing step of applying a water washing process by blowing washing water onto the PS plate, a desensitizing step of performing a desensitizing process by coating a desensitizing process liquid such as a gum liquid onto the surface of the PS plate after the water washing process.
According to the desensitizing process step for the PS plate, a thin film for protecting the plate surface is formed on the front and rear surfaces of the PS plate by coating a gum liquid evenly on the front and rear surfaces of the PS plate while conveying the PS plate by a conveying roller pair disposed outside the stored gum liquid, and squeezing off the excessive gum liquid by the conveying roller pair.
Here, when the gum liquid used for the desensitizing process for the PS plate is adhered to the circumferential surface of the conveying roller pair (roller), problems such as rotation disability of the roller pair, conveyance failure, pollution, damage and the like of the PS plate may occur. Therefore, in the PS plate processor, the circumferential surface of the roller to which the gum liquid adheres is washed with a washing liquid according to a preset schedule such as the time of stopping the drive of the PS plate after finishing the PS plate processes so as to wash off the gum liquid from the roller surface.
Additionally, among the PS plates, there is one having a width of about 1100 mm orthogonal to the conveyance direction. In a PS plate processor for processing such a PS plate, the length along the axis direction of the roller for conveying the PS plate is elongated as well. The elongated roller has difficulty in evenly supplying a washing liquid in the axis. Thus a larger amount of the washing liquid is used for removing the gum liquid from the roller successfully. Consequently, the amount of waste liquid increases as well.
Moreover, among the PS plate processors, there is one using the washing liquid after washing the roller as a diluting liquid for the gum liquid. According to this PS plate processor, a problem exists that the gum liquid can be diluted excessively due to the large amount of the washing liquid for removing the gum liquid from the roller (second problem).
Next, the PS plate is treated in the developing process after the image-wise exposure. According to the PS plate processor for treating the PS plate, the developing process is performed while conveying the PS plate soaked in the developing liquid stored in the developing vessel.
A heater and the like for heating the developing liquid to a predetermined temperature is provided in the developing vessel so as to maintain a temperature range of the optimum processing state of the PS plate. Moreover, according to the PS plate processor, the developing liquid in the developing vessel is agitated by suctioning the developing liquid in the developing vessel and jetting the developing liquid from a spray pipe disposed on one side of the PS plate conveying path in the developing vessel so as to prevent developing irregularity due to the temperature irregularity and the like.
In a submerged spray method where a developing liquid is sprayed from a spray pipe with an axis direction disposed along the PS plate width direction, the developing liquid on one side can not easily be agitated in the direction orthogonal to the axis direction while the developing liquid on the other side of the PS plate can easily be agitated. Due to this, substituting the developing liquid may delay.
Therefore, when an environmental temperature is lower than the developing liquid temperature, the developing liquid temperature will differ at the circumferential rim of the PS plate. Such a temperature difference will lead to a sensitivity difference in the PS plate after the developing process. As a result the finish quality of the PS plate will be deteriorated. For example, the temperature difference of about 0.2° C. causes the sensitivity difference of about 5 to 10%.
In contrast, a lateral jetting method allows jetting a developing liquid in the direction orthogonal to the PS plate conveyance direction from an outer side of the PS plate width direction. As a result the temperature difference in the circumferential rim of the PS plate can be prevented even with a low environmental temperature since substituting the developing liquid can be performed rapidly in the vicinity of the PS plate surface.
However, in the lateral jetting method, difference occurs in the flow rate of jetted developing liquid; one rate in the vicinity of the jetting opening differs from another rate at a position away from the jetting opening. The developing liquid flow rate difference will lead to the difference in the progress of development. That is, the development is promoted in a region with a higher developing liquid flow rate compared with another region with a lower developing liquid flow rate. Consequently, the sensitivity difference will appear locally (third problem).
Next, the PS plate processor as the photosensitive material processing device for processing the PS plate comprises a pair of side plates for laying the PS plate on the conveying roller for conveyance. The pair of side plates is disposed in a processing vessel for storing a processing liquid such as a developing liquid. With the driving force transmitted to the conveying roller, the conveying roller conveys the PS plate.
In such a PS plate processor, the convenience of maintaining the driving system generally leads to disposing a drive shaft along the PS plate conveyance direction and on one end side of the direction orthogonal to the PS plate conveyance direction. The drive shaft transmits the driving force to each conveying roller. Here, by providing a worm gear in the drive shaft and a helical gear in the side plates, and elongating the rotation shaft provided with the helical gear in the direction orthogonal to the PS plate conveyance direction, the driving force is transmitted to the conveying roller.
Here, in the combination of the worm gear and the helical gear, the speed reduction ratio is 4 to 12 times. That is, the worm gear on the driving source side transmits the driving force to the helical gear on the side plate side, reducing the speed.
Furthermore, in the PS plate processor, conveyance failure of the PS plate such as jamming may occur. In this case, removing the jammed PS plate immediately can resume processing of the PS plate.
However, when the so-called jamming as the PS plate conveyance failure occurs, the roller will be locked. At the time, a large torque acts on the helical gear side since the speed reduction ratio is large in the driving system using a combination of the worm gear and the helical gear. As a result, the helical gear or the other gears on the side plate side may be damaged (fourth problem).
Next, a gum liquid used for the desensitizing process of the PS plate includes a component of a gum arabic or the like. When rotating the conveying roller pair is stopped with the gum liquid adhered to the surface of the conveying roller pair and the adhered liquid is left as it is, the component in the gum liquid will precipitate and fix on the circumferential surface of the roller.
Accordingly, if the gum liquid is adhered to the contact part of the rollers comprising the conveying roller pair, the rollers can attach to each other due to the gum liquid. With this attaching state, rotating the conveying roller pair causes a large torque on a gear for transmitting the driving force to the rollers so as to result in breakage of the gear (fifth problem).
The PS plates include conventionally existing commonly used PS plates (conventional), thermal plates, and photo polymer plates. The commonly used PS plates include the positive type and the negative type. And furthermore, each of them has a one side type provided with a photosensitive layer on one surface of the supporting body, and a both side type provided with a photosensitive layer on both surfaces. Moreover, the photo polymer plates are, in general, a one surface type (one side type) and a negative type, but the thermal plates are one surface type (one side type) and both negative type and positive type.
The PS processors include for example, those including a conveying path for the PS plate with conveying roller pairs in a developing vessel, those including a conveying path with conveying rollers and guide plates, and those with brush rollers, depending on the kind of the PS plate to be processed. Moreover, the number of the brush rollers depends on the kind of the PS plate (such as the one side type or the both side type).
That is, among the PS plate processors, despite of a common processing tank such as a developing vessel, there are those including arranging of conveying rollers and brush rollers corresponding to the kind of the PS plates to be processed. Furthermore, modifying the conveying path configuration has been discussed and practiced so as to make the PS plate processor capable of processing different PS plates.
In the PS plate processors, a replenishing liquid is replenished according to the PS plate process amount and for compensating the aging deterioration of the developing liquid as well as the developing liquid in the developing vessel is replaced per certain period. Consequently, the processing performance of the developing liquid is always maintained so as to enable the optimum developing process.
The basic liquid of the developing liquid and the replenishing liquid for replenishment to be introduced into the developing vessel at the time of periodical replacing the developing liquid may be those prepared by diluting a common original liquid with a common diluting ratio. Diluting ratios may be different between the basic liquid and the replenishing liquid. Further, the basic liquid may differ from the replenishing liquid.
In general, a certain amount of the original liquid for the basic liquid is contained in a bottle. When a preparation liquid as the basic liquid for processing the PS plate is newly prepared, the original liquid and the diluting water are preliminarily prepared according to the capacity of the developing vessel and the preparation liquid is supplied to the developing vessel. If the developing vessel capacity changes, the preparation liquid must be prepared according to the changed capacity.
That is, although the original capacity of the developing vessel in the processing tank remains the same, the net capacity of the developing vessel (the storable amount of the developing liquid) depends on the number of the rollers, guide plates, and brush rollers to be disposed inside the developing vessel. Therefore, for the PS plate processors with different developing vessel capacities, it is difficult to commonly use a preparation device for preparing a preset amount of the preparation liquid.
Therefore, a method of preparing the preparation liquid by directly introducing the original liquid and the diluting water into the developing vessel is conceivable.
Here, the PS plate processor is provided with a replenishing mechanism for supplying the original liquid and the water (diluting water) for replenishing the replenishing liquid to the developing vessel. In the replenishing mechanism, the replenishing liquid (the original liquid and the water for dilution) can be supplied accurately to the developing vessel using a bellows pump corresponding to the PS plate processing amount and the time.
When the preparation liquid is prepared in the developing vessel, a large amount of water should be supplied in a short time into the developing vessel with the original liquid preliminarily stored. Accordingly, the water is supplied using a magnet pump, monitoring the liquid level with a float sensor.
However, when a pump with high ejection ability such as a magnet pump makes it difficult to supply an amount of water accurately and appropriately to the original liquid with the liquid level monitored. Moreover, when the diluting ratio of a predetermined amount of the original liquid depends on the kind of the PS plate, the amount of the diluting water to be added to the original liquid must be changed. This hinders versatility of a device for replenishing (sixth problem).